I. K. Ravichandra Rao

Classification of growth models based on growth rates and its applications

In this paper, growth models are classified and characterised using two types of growth rates: from time t to t+1 and from time t to 2t. They are interesting in themselves but can also be used for a quick prediction of the type of growth model that is valid in a particular case. These ideas are applied on 20 data sets collected byWolfram, Chu andLu. We determine (using the above classification as well as via nonlinear regression techniques) that the power model (with exponent>1) is the best growth model for Sci-Tech online databases, but that Gompertz-S-shaped distribution is the best for social sciences and humanities online databases.

Citation age data and the obsolescence function: Fits and explanations

LOUVAIN UNIV CATHOLIC,B-3590 DIEPENBEEK,BELGIUM. RV COLL,CTR DOCUMENTAT RES & TRAINING,BANGALORE 560059,INDIA.EGGHE, L, UNIV INSTELLING ANTWERP,UNIV PLEIN 1,B-2610 WILRIJK,BELGIUM.

An analysis of Bradford multipliers and a model to explain law of scattering

In his book on “Documentation”, Bradford derived the law of scattering, based on algebric explanation with the supposition that n1=n2=n. n1 and n2 are computed based on average no. of articles per journals in the first three zones. An analysis of a small sample of 12 data sets, using t-test suggests that it is unlikely that n1=n2. Further an attempt has been made to identify a suitable model to explain the law of scattering; among the various models tried, log-normal fits much better than many models including the log-linear model.

On the influence of production on utilization functions: Obsolescence or increased use?

We study the influence of production on utilization functions. A concrete example of this is the influence of the growth of literature on the obsolescence (aging) of this literature. Here, synchronous as well as diachronous obsolescence is studied. Assuming an increasing exponential function for production and a decreasing one for aging, we show that, in the synchronous case, the larger the increase in production, the larger the obsolescence. In the diachronous case the opposite relation holds: the larger the increase in production the smaller the obsolescence rate. This has also been shown previously byEgghe but the present proof is shorter and yields more insight in the derived results. If a decreasing exponential function is used to model production the opposite results are obtained. It is typical for this study that there are two different time periods: the period of production (growth) and — per year appearing in the production period — the period of aging (measured synchronously and diachronously). The interaction of these periods is described via convolutions (discrete as well as continuous).

Empirical series of journal h-indices: The JCR category Horticulture as a case study

AbstractTwo types of series of h-indices for journals published in the field of Horticulture during the period 1998–2007 are calculated. Type I h-indices are based on yearly data, while type II h-indices use cumulative data. These h-indices are also considered in a form normalised with respect to the number of published articles.It is observed that type I h-indices, normalised or not, decrease linearly over a period of ten years. The type II series, however, is not linear in nature: it exhibits partly a concave shape. This proves that the journals (in Horticulture) do not exhibit a linear increase in h-index as argued by Hirsch in the case of life-time achievements of scientists.In the second part of the paper, an attempt is made to study the relative visibility of a journal and its change over time, based on h-indices of journals. It is shown that: the h-index over the complete period 1998–2007 of the journal Theoretical & Applied Genetics (h = 62) is much higher than that of all other journals in the fieldthe relation between the number of publications and the type II h-index for the whole period is not an exact power law (as it would have to be if the Egghe-Rousseau model were applicable)in order to study the dynamic aspects of journal visibility, a field-relative normalised h-ratio is defined to monitor systematic changes in the field of Horticulture. Except for two journals, the Pearson correlation coefficient for yearly values of this field-relative normalised h-ratio indicates that there is no systematic change of the performance of the journals with respect to the field as a whole.

Duality revisited: construction of fractional frequency distributions based on two dual Lotka laws

Fractional frequency distributions of, for example, authors with a certain (fractional) number of papers are very irregular and, therefore, not easy to model or to explain. This article gives a first attempt to this by assuming two simple Lotka laws (with exponent 2): one for the number of authors with n papers (total count here) and one for the number of papers with n authors, n ∈ N. Based on an earlier made convolution model of Egghe, interpreted and reworked now for discrete scores, we are able to produce theoretical fractional frequency distributions with only one parameter, which are in very close agreement with the practical ones as found in a large dataset produced earlier by Rao. The article also shows that (irregular) fractional frequency distributions are a consequence of Lotkas law, and are not examples of breakdowns of this famous historical law.

Growth of food science and technology literature: A comparison of CFTRI, India and the world

An attempt has been made to trace and compare the trends in growth of Food Science and Technology (FST) literature (periodical articles, patents, standards, theses and dissertations) produced by CFTRI scientists, by food scientists in India and by food scientsts of the world, covering a period between 1950 and 1990; to identify the best fitting growth models for actual and cumulative growth of data through regression analysis; and αt and α2t analysis; and to compute and compare the growth rates of FST documnets.

A quantitative study of Indian engineering literature

In recent years, several projects were sponsored by NISSAT of the Goverment of India to map Indian Science. As a part of it, a database (COMPENDEX) in engineering field was analysed. It has been found that engineers in India publish their articles mostly in journals; almost all of them publish in English language. They publish in a selected few journals. Only a few of the institutions are concentrated in engineering research. It has been observed that research output in applied physics, light & optics, bioengineering and information science are increasing both at the world and India level. In the area of energy technology metallurgical engineering and food technology, research output is decreasing at both levels.

Methodological and conceptual questions of bibliometric standards

Bibliometric studies are mostly empirical nature and they are mostly centred arround presentation of facts and data. There are very few studies which are centred arround theoretical foundation. The facts are gathered either through surveys or from published bibliographies, indexes, data bases. Based on these facts, empirical models and principles are being developed. The normative principles and standards have to evolve from the logical analyses of the empirical models. The stage is set to integrate empirical models of bibliometrics into standards. Future, bibliometrics studies have to address this issue and reach the stage of normative principles.

Distributions of Multiple Authors: A Case Study of two Journals (JASIST and Scientometrics)

Data on distributions of multiple authors in two journals namely, JASIST and Scientometrics, were collected and analyzed. The number of authors per paper in both the journals is increasing; it therefore indicates the trend towards collaboration with more than two authors. i.e., the collaborating nature of research is gradually shifting from 2-authored papers to more than two authors per paper.Data on distributions of multiple authors in two journals namely, JASIST and Scientometrics, were collected and analyzed. The number of authors per paper in both the journals is increasing; it therefore indicates the trend towards collaboration with more than two authors. i.e., the collaborating nature of research is gradually shifting from 2-authored papers to more than two authors per paper.